6561577537 has 2 divisors, whose sum is σ = 6561577538. Its totient is φ = 6561577536.

The previous prime is 6561577501. The next prime is 6561577543. The reversal of 6561577537 is 7357751656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5775392016 + 786185521 = 75996^2 + 28039^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6561577537 is a prime.

It is not a weakly prime, because it can be changed into another prime (6561577937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280788768 + 3280788769.

It is an arithmetic number, because the mean of its divisors is an integer number (3280788769).

Almost surely, 2^6561577537 is an apocalyptic number.

It is an amenable number.

6561577537 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561577537 is an equidigital number, since it uses as much as digits as its factorization.

6561577537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4630500, while the sum is 52.

The square root of 6561577537 is about 81003.5649647594. The cubic root of 6561577537 is about 1872.1303694218.

The spelling of 6561577537 in words is "six billion, five hundred sixty-one million, five hundred seventy-seven thousand, five hundred thirty-seven".